A luminous body when obscured by a dense atmosphere will appear smaller; as may be seen by the moon or sun veiled by fogs. - Leonardo da Vinci

Many will think they may reasonably blame me by alleging that my proofs are opposed to the authority of certain men held in the highest reverence by their inexperienced judgments; not considering that my works are the issue of pure and simple experience, who is the one true mistress. These rules are sufficient to enable you to know the true from the false — and this aids men to look only for things that are possible and with due moderation — and not to wrap yourself in ignorance, a thing which can have no good result, so that in despair you would give yourself up to melancholy.

Be not false about the past.

The function which the wing performs against the air when the air is motionless is the same as that of the air moved against the wings when these are without motion.